The invention relates to abrasion resistant coated articles, for example, cutting tools.
Metal cutting and other wear applications require cutting tools and abrasive materials with particular surface and bulk properties. The tool surface must be chemically inert and resistant to mechanical wear, while the bulk material must be tough and resistant to plastic deformation, as well as to crack generation and propagation. These requirements have been satisfied by substrate and applied coating optimization.
Titanium and its alloys present particular challenges for cutting tool design. Titanium is characterized by a low thermal conductivity, a low specific heat, and a high melting point. These properties result in high cutting temperatures even at moderate cutting speeds. Furthermore, titanium displays high chemical reactivity at these high cutting temperatures. To date, no coated cutting tool has been found to be satisfactory for titanium machining. Currently, the best available tool material for titanium machining is cemented tungsten carbide cobalt (WC--Co), which maintains shape integrity only at extremely low cutting speeds. Cutting tools are needed capable of machining titanium and other hard to machine materials at high speeds and feed rates. The invention described herein was developed to address this need.